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1.
Global climate change is expected to result in greater variation in snow cover and subsequent impacts on land surface hydrology and vegetation production in the high Trans Himalayan region (THR). This paper examines how the changes in timing and duration of snow cover affect the spatio-temporal pattern of rangeland phenology and production in the region. Moderate Resolution Imaging Spectrometer (MODIS) 16-day normalized difference vegetation index (NDVI) data from 2000 to 2009 and concurrent snow cover, precipitation and temperature data were analyzed. In contrast to numerous studies which have suggested that an earlier start of the season and an extension of the length of the growing season in mid and higher latitude areas due to global warming, this study shows a delay in the beginning of the growing season and the peak time of production, and a decline in the length of growing season in the drier part of THR following a decline and a delay in snow cover. Soil moisture in the beginning of the growing season and consequent rangeland vegetation production in drier areas of the THR was found to be strongly dependent upon the timing and duration of snow cover. However, in the wetter part of the THR, an earlier start of season, a delay in end of season and hence a longer growing season was observed, which could be attributed to warming in winter and early spring and cooling in summer and late spring and changes in timing of snow melt. The study shows a linear positive relationship between rangeland vegetation production and snow cover in the drier parts of THR, a quadratic relationship near to permanent snow line, and a negative linear relationship in wetter highlands. These findings suggest that, while temperature is important, changes in snow cover and precipitation pattern play more important roles in snow-fed, drier regions for rangeland vegetation dynamics. 相似文献
2.
Phenology shift from 1989 to 2008 on the Tibetan Plateau: an analysis with a process-based soil physical model and remote sensing data 总被引：1，自引：0，他引：1
Phenology is critical to ecosystem carbon quantification, and yet has not been well modeled considering both aboveground and belowground environmental variables. This is especially true for alpine and pan-arctic regions where soil physical conditions play a significant role in determining the timing of phenology. Here we examine how the spatiotemporal pattern of satellite-derived phenology is related to soil physical conditions simulated with a soil physical model on the Tibetan Plateau for the period 1989–2008. Our results show that spatial patterns and temporal trends of phenology are parallel with the corresponding soil physical conditions for different study periods. On average, 1 °C increase in soil temperature advances the start of growing season (SOS) by 4.6 to 9.9 days among different vegetation types, and postpones the end of growing season (EOS) by 7.3 to 10.5 days. Soil wetting meditates such trends, especially in areas where warming effect is significant. Soil thermal thresholds for SOS and EOS, defined as the daily mean soil temperatures corresponding to the phenological metrics, are spatially clustered, and are closely correlated with mean seasonal temperatures in Spring and Autumn, respectively. This study highlights the importance and feasibility of incorporating spatially explicit soil temperature and moisture information, instead of air temperature and precipitation, into phenology models so as to improve carbon modeling. The method proposed and empirical relations established between phenology and soil physical conditions for Alpine ecosystems on the Tibetan plateau could also be applicable for other cold regions. 相似文献
3.
Yanfang Wang Yanjun Shen Fubao Sun Yaning Chen 《Theoretical and Applied Climatology》2014,118(3):569-579
Temperature has long been accepted as the major controlling factor in determining vegetation phenology in the middle and higher latitudes. The influence of water availability is often overlooked even in arid and semi-arid environments. We compared vegetation phenology metrics derived from both in situ temperature and satellite-based normalized difference vegetation index (NDVI) observations from 1982 to 2006 by an example of the arid region of northwestern China. From the satellite-based results, it was found the start of the growing season (SOS) advanced by 0.37 days year?1 and the end of the growing season (EOS) delayed by 0.61 days year?1 in Southern Xinjiang over 25 years. In the Tianshan Mountains, the SOS advanced by 0.35 days year?1 and the EOS delayed by 0.31 days year?1. There were almost no changes in Northern Xinjiang. Compared with satellite-based results, those estimates based on temperature contain less details of spatial variability of vegetation phenology. Interestingly, they show different and at times reversed spatial patterns from the satellite results arising from water limitation. Phenology metrics derived from temperature and NDVI conclude that water limitation of onset of the growing season is more severe than the cessation. Phenology spatial patterns of four oases in Southern Xingjiang show that, on average, there is a delay of the SOS of 1.6 days/10 km of distance from the mountain outlet stations. Our results underline the importance of water availability in determining the vegetation phenology in arid regions and can lead to important consequences in interpreting the possible change of vegetation phenology with climate. 相似文献
4.
基于GIMMS（global inventory modeling and mapping studies）NDVI 3g数据,在提取北半球荒漠草原过渡带每年植被物候期的基础上,研究了1982-2012年物候期的时间演化趋势及空间分异特征,并结合全球气候再分析资料,探讨了物候变化的气候驱动因素。结果表明：在1998年之前,荒漠草原过渡带植被物候期变化地区间差异较大,而在1998年之后,北半球荒漠草原过渡带生长季结束期整体提前,平均提前0.41 d/a;同时,除萨赫勒以外的各地区植被生长季长度普遍缩短,平均缩短0.88 d/a。植被物候期与气候因子的相关分析发现,荒漠草原过渡带植被物候变化受气候变化影响显著,且空间差异明显。在中高纬度地区,气温是限制植被活动的关键因子,温度升高可以促进生长季开始期的提前,而降水增加则会妨碍植被生长;在较低纬度地区,水分是影响植被活动的关键因素,高温造成的水分亏缺会导致植被生长季缩短。从植被物候期对各气候因子响应的时滞性来看,荒漠草原过渡带植被的物候期对气温变化的响应最迅速,对蒸散的响应存在一定的滞后性,而对降水的响应不存在时滞差异。 相似文献
5.
基于遥感数据的内蒙古草原灌丛物候变化研究 总被引：1，自引：0，他引：1
植被物候研究是全球气候变化研究的重要内容,但国际上有关干旱半干旱区灌丛物候变化的研究还很缺乏。为了探讨气候变化对内蒙古草原灌丛物候的影响,利用2000~2011年的MODIS EVI时间序列影像,采用动态阈值法得到6种灌丛12 a物候年际变化情况,结合样点附近气象站的气温和降水数据,分析了灌丛物候与气候变化的动态关系。结果表明：（1）内蒙古中西部草原灌丛返青期、枯黄期都呈现提前的趋势,生长季长度缩短;（2）春季均温升高和前一年秋冬降水增加可以提前灌丛返青期,是影响返青期的主要因素;（3）秋季降水减少和夏秋均温上升都利于枯黄期提前,夏季降水的作用则因灌丛种类不同而略有差异;（4）夏秋均温上升缩短了生长季长度,夏秋降水量、春季均温则多与生长季长度呈正相关。 相似文献
6.
Using the high-quality observed meteorological data,changes of the thermal conditions and precipitation over the North China Plain from 1961 to 2009 were examined.Trends of accumulated temperature and negative temperature,growing season duration,as well as seasonal and annual rainfalls at 48 stations were analyzed.The results show that the accumulated temperature increased significantly by 348.5℃ day due to global warming during 1961 2009 while the absolute accumulated negative temperature decreased apparently by 175.3℃ day.The start of growing season displayed a significant negative trend of-14.3 days during 1961-2009,but the end of growing season delayed insignificantly by 6.7 days.As a result,the length of growing sea.son increased by 21.0 days.The annual and autumn rainfalls decreased slightly while summer rainfall and summer rainy days decreased significantly.In contrast,spring rainfall increased slightly without significant trends.All the results indicate that the thermal conditions were improved to benefit the crop growth over the North China Plain during 1961-2009,and the decreasing annual and summer rainfalls had no direct negative impact on the crop growth.But the decreasing summer rainfall was likely to influence the water resources in North China,especially the underground water,reservoir water,as well as river runoff,which would have influenced the irrigation of agriculture. 相似文献
7.
Changes of Accumulated Temperature, Growing Season and Precipitation in the North China Plain from 1961 to 2009 
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下载免费PDF全文 Using the high-quality observed meteorological data, changes of the thermal conditions and precipitation over the North China Plain from 1961 to 2009 were examined. Trends of accumulated temperature and negative temperature, growing season duration, as well as seasonal and annual rainfalls at 48 stations were analyzed. The results show that the accumulated temperature increased significantly by 348.5℃ day due to global warming during 1961-2009 while the absolute accumulated negative temperature decreased apparently by 175.3℃ day. The start of growing season displayed a significant negative trend of -14.3 days during 1961- 2009, but the end of growing season delayed insignificantly by 6.7 days. As a result, the length of growing season increased by 21.0 days. The annual and autumn rainfalls decreased slightly while summer rainfall and summer rainy days decreased significantly. In contrast, spring rainfall increased slightly without significant trends. All the results indicate that the thermal conditions were improved to benefit the crop growth over the North China Plain during 1961-2009, and the decreasing annual and summer rainfalls had no direct negative impact on the crop growth. But the decreasing summer rainfall was likely to influence the water resources in North China, especially the underground water, reservoir water, as well as river runoff, which would have influenced the irrigation of agriculture. 相似文献
8.
Global warming exerts a lengthening effect on the growing season, with observational evidences emerging from different regions over the world. However, the difficulty for a global overview of this effect for the last century arises from limited availability of the long-term daily observations. In this study, we find a good linear relationship between the start (end) date of local growing season (LGS) and the monthly mean temperature in April (October) using the global gridded daily temperature dataset for 1960–1999. Using homogenized daily temperature records from nine stations where the time series go back to the beginning of the twentieth century, we find that the rate of change in the start (end) date of the LGS for per degree warming in April (October) mean temperature keeps nearly constant throughout the time. This enables us to study LGS changes during the last century using global gridded monthly mean temperature data. The results show that during the period 1901–2009, averaged over the observation areas, the LGS length has increased by a rate of 0.89 days decade?1, mainly due to an earlier start (?0.58 days decade?1). This is smaller than those estimates for the late half of the twentieth century, because of multidecadal climate variability (MDV). A MDV component of the LGS index series is extracted by using Ensemble Empirical Mode Decomposition method. The MDV exhibits significant positive correlation with the Atlantic Multi–decadal Oscillation (AMO) over most of the Northern Hemisphere lands, but negative in parts of North America and Western Asia for start date of LGS. These are explained by analyzing differences in atmospheric circulation expressed by sea level pressure departures between the warm and cool phases of AMO. It is suggested that MDV in association with AMO accelerates the lengthening of LGS in Northern Hemisphere by 53 % for the period 1980–2009. 相似文献
9.
利用我国南方稻区214站1961—2009年逐日气象资料,研究气候变化对南方水稻可种植区的影响。研究结果显示：气候变暖使南方稻区活动积温（日平均气温≥10℃）明显增加,49年增加了324.4℃?d。同时水稻生长季长度也明显延长,49年延长了17.9 d。双季稻可种植区北界明显北移,三季稻可种植区北界略有北移,20世纪60—80年代,双季稻可种植区仅限于长江以南地区,但21世纪初以来的10年双季稻可种植区北界移到长江以北,即向北推移近300 km,从而使新增双季稻可种植区扩展到四川东北部、贵州东部、重庆、湖北大部、安徽中部以及江苏南部。 相似文献
10.
利用区域气候模式RegCM4的逐日气温和降水资料,预估1.5℃和2.0℃升温情景下,东北地区平均气候和极端气候事件的变化。结果表明：RCP4.5排放情景下,模式预计在2030年和2044年左右稳定达到1.5℃和2.0℃升温;两种升温情景下,东北地区气温、积温、生长季长度均呈增加趋势,且增幅随着升温阈值的升高而增加;1.5℃升温情景下,年平均气温增幅为1.19℃,年平均降水距平百分率增幅为5.78%,积温增加247.1℃·d,生长季长度延长7.0 d;2.0℃升温情景下气温、积温、生长季长度增幅较1.5℃升温情景下显著,但是年和四季降水普遍减少,年降水距平百分率减小1.96%。两种升温情景下,极端高温事件显著增加,极端低温事件显著减少,极端降水事件普遍增加。霜冻日数、结冰日数均呈显著减少趋势,热浪持续指数呈显著增加趋势;未来东北地区降水极端性增强,不仅单次降水过程的量级增大,极端降水过程的量级也明显增大,随着升温阈值的增大,极端降水的强度也逐渐增大。 相似文献
11.
在全球变暖背景下,中国区域生长季发生了改变,但以往研究时段偏短、数据分辨率低且空间覆盖相对有限。本文利用0.25°×0.25°高水平分辨率日平均气温资料CN05.1,研究了1961～2018年中国生长季开始日、结束日和长度的气候态特征、变化趋势及其与季节平均温度的关系。结果表明,1961～2018年中国平均生长季开始日和结束日分别为3月31日和10月29日,长度为212 d。空间上,开始日由东南向西北逐渐推迟,结束日呈反向变化,长度由东南向西北缩短。整体而言,1961～2018年中国平均生长季开始日提前、结束日推迟、长度延长,其速率分别为?1.3 d (10 a)?1、0.9 d (10 a)?1、2.2 d (10 a)?1,其中开始日提前对长度延长的影响更大。此外,中国平均生长季开始日提前和长度增加主要源于春季升温,而结束日推迟则与秋季变暖有关。 相似文献
12.
中国东部季风区植被物候季节变化对气候响应的大尺度特征：年际比较 总被引：12，自引：1，他引：11
利用1982～1993年NOAA/NASA PathfinderAVHRR陆地数据集中的NDVI数据集,在中国东部植被生长的不同阶段(全年、植被生长季、植被生长季的增长阶段和衰退阶段),对植被季节生长对气候响应的年际变化进行了分析,发现：(1)无论在多年平均意义上还是逐年来看,中国东部季风区植被季节性生长状况对温度的响应在各个生长阶段都是近于同步的,温度对于植被生长季节变化的驱动关系非常稳定;(2)逐年来看,植被季节性生长对降水的响应也是存在的,但相关关系和相关的滞后关系具有年际差异。通过定量化地分析中国东部植被季节生长对季风气候响应的年际变化,有助于对陆面过程模式中的有关部分进行改进,从而提高对中国东部区域年际气候变化的模拟能力。 相似文献
13.
Jee-Hoon Jeong Jong-Seong Kug Baek-Min Kim Seung-Ki Min Hans W. Linderholm Chang-Hoi Ho David Rayner Deliang Chen Sang-Yoon Jun 《Climate Dynamics》2012,38(7-8):1421-1431
We present a study that suggests greening in the circumpolar high-latitude regions amplifies surface warming in the growing season (May–September) under enhanced greenhouse conditions. The investigation used a series of climate simulations with the Community Atmospheric Model version 3—which incorporates a coupled, dynamic global vegetation model—with and without vegetation feedback, under both present and doubled CO2 concentrations. Results indicate that climate warming and associated changes promote circumpolar greening with northward expansion and enhanced greenness of both the Arctic tundra and boreal forest regions. This leads to additional surface warming in the high-latitudes in the growing season, primarily through more absorption of incoming solar radiation. The resulting surface and tropospheric warming in the high-latitude and Arctic regions weakens prevailing tropospheric westerlies over 45–70N, leading to the formation of anticyclonic pressure anomalies in the Arctic regions. These pressure anomalies resemble the anomalous circulation pattern during the negative phase of winter Arctic Oscillation. It is suggested that these circulation anomalies reinforce the high-latitude and Arctic warming in the growing season. 相似文献
14.
Effects of observed and experimental climate change on terrestrial ecosystems in northern Canada: results from the Canadian IPY program 总被引：1，自引：0，他引：1
Gregory H. R. Henry Karen A. Harper Wenjun Chen Julie R. Deslippe Robert F. Grant Peter M. Lafleur Esther Lévesque Steven D. Siciliano Suzanne W. Simard 《Climatic change》2012,115(1):207-234
Tundra and taiga ecosystems comprise nearly 40?% of the terrestrial landscapes of Canada. These permafrost ecosystems have supported humans for more than 4500?years, and are currently home to ca. 115,000 people, the majority of whom are First Nations, Inuit and Métis. The responses of these ecosystems to the regional warming over the past 30?C50?years were the focus of four Canadian IPY projects. Northern residents and researchers reported changes in climate and weather patterns and noted shifts in vegetation and other environmental variables. In forest-tundra areas tree growth and reproductive effort correlated with temperature, but seedling establishment was often hindered by other factors resulting in site-specific responses. Increased shrub cover has occurred in sites across the Arctic at the plot and landscape scale, and this was supported by results from experimental warming. Experimental warming increased vegetation cover and nutrient availability in most tundra soils; however, resistance to warming was also found. Soil microbial diversity in tundra was no different than in other biomes, although there were shifts in mycorrhizal diversity in warming experiments. All sites measured were sinks for carbon during the growing season, with expected seasonal and latitudinal patterns. Modeled responses of a mesic tundra system to climate change showed that the sink status will likely continue for the next 50?C100?years, after which these tundra systems will likely become a net source of carbon dioxide to the atmosphere. These IPY studies were the first comprehensive assessment of the state and change in Canadian northern terrestrial ecosystems and showed that the inherent variability in these systems is reflected in their site-specific responses to changes in climate. They also showed the importance of using local traditional knowledge and science, and provided extensive data sets, sites and researchers needed to study and manage the inevitable changes in the Canadian North. 相似文献
15.
全球变暖背景下中国东部气候变迁及其对物候的影响 总被引：1，自引：0，他引：1
鉴于我国东部地区对全球气候变化的高度敏感性,本文应用1960~2014年的CRU和HadISST等全球地表（地球表面的简称,包括陆地和海洋表面,下同）温度再分析资料,采用地理等温线和春、秋季（代表月地表温度）时间的变迁速度等指标,分析了全球和中国东部地区的气候变化速度以及春、秋季物候的变化。结果显示:（1）自1960年以来,全球地表温度呈现十分清晰的上升趋势,其中,北半球（陆地）比南半球（海洋）变暖更显著,地理等温线向两极方向迁移;（2）南、北半球的春（秋）季明显提前（滞后）;（3）中国东部地表温度呈快速上升趋势,陆地升温虽普遍快于海洋,但东部海域升温快于相邻的陆地,地理等温线总体向北迁移,海域的春、秋季物候变化较陆地显著;（4）中国东部生物物候受气候变化影响明显,海域地理等温线的北移受到沿岸地形的抑制,海洋生物适应气候变化的能力受到限制,海洋生态系统及生物多样性将面临气候变化带来的显著风险。 相似文献
16.
中国木本植物物候对气温变化的响应 总被引：1，自引：0，他引：1
本文利用全国21个站的木本植物物候资料和全国599个站的逐日气温资料,分析了1963~1988年中国木本植物物候对气温变化的响应,研究表明:26年来,植物春季物候期与春季气温在全国总体呈负相关,气温越高,物候期越提前;植物秋季物候期与秋季气温在全国呈正相关,但相关性没有春季物候期显著;我国木本植物物候生长季长度有明显的南-北向梯度,早春气温对植物物候生长季的影响比秋末气温对其影响更大。 相似文献
17.
基于MODIS的MCD12Q2数据,采用趋势分析和相关性分析方法,结合遥感降水和气温数据产品,探求了天山新疆段2001—2014年植被物候的时空变化及其影响因素的相对作用。天山新疆段植被物候始期呈明显的垂直地带性分布特征,集中于3月10日至5月15日,全区14年平均值为3月20日;植被物候末期具有纬度地带性分布特征,集中于10月1日至10月25日。天山新疆段植被物候始期在山区呈不显著推迟趋势,绿洲和平原呈不显著提前趋势;植被物候末期主要呈不显著提前趋势;降水量和气温是影响天山植被物候期的重要因素。物候始期受当年春季气温的影响最为显著,也受到前一年冬季降水量的影响,其与降水量呈正相关,与气温呈负相关。夏季和秋季降水量是天山新疆段植被物候末期的主要影响因素。 相似文献
18.
19.
基于温度、降水、光照等指标,通过利用区域气候模式所预估的分辨率为1°(纬度)×1°(经度)的未来气候预估数据,对1981~2005年的基准期和RCP4.5、RCP8.5两排放情景下2069~2098年中国热量资源以及冬小麦种植界限、理论生育期和气候适宜种植分区的空间分布特征进行了对比分析。研究主要结论为:与基准期相比,两未来气候变化情景下我国热量资源、冬小麦种植条件与气候适宜性差异显著。且相比于RCP4.5情景,在RCP8.5情景下中国2069~2098年多数地区热量资源增加、冬小麦种植北界和南界北移东扩、可种植面积扩大,多数区域理论适宜播种期推迟、理论成熟期提前、潜在生长季缩短,且潜在生长季内的光—温—水配置使得冬小麦气候适宜性有所提高。但由于冬小麦为喜凉作物,对高温胁迫非常敏感,RCP8.5情景下更多的极端高温天气和不对称增温等因素带来的负面影响很可能抵消前述光—温—水配置所带来的有利影响,从而降低冬小麦的种植适宜性。因此,未来研究工作仍应致力于减缓气候变化,以保障我国粮食生产的安全。 相似文献
20.
Man-yu Dong Yuan Jiang Da-yong Zhang Zheng-fang Wu 《Theoretical and Applied Climatology》2013,111(3-4):693-701
Daily mean air temperatures from 81 meteorological stations in Northeast China were analyzed for the spatiotemporal change of the climatic growing season during the period 1960–2009. Our results showed that latitude strongly influenced the spatial patterns of the mean start (GSS), end (GSE), and length (GSL) of the growing season. For the area studied, a significant increasing trend in GSL during 1960–2009 was detected at a significance level of 0.01, especially after the early 1980s. The area-average GSL has extended 13.3 days during the last 50 years, mainly due to the advanced GSS evident in the spring (7.9 days). The variations of GSS and GSE were closely correlated with the monthly mean temperature (T mean) of April and October, respectively, while GSL was closely related to the monthly minimum temperatures (T min) of spring (March to April) and autumn (September to October). The distributions of the trends in growing season parameters (GSS, GSE, and GSL) showed great spatial variability over Northeast China. Significant relationships between altitude and the trend rates of the GSS and GSL were detected, while geographic parameters had little direct effect on the change in GSE. This extended growing season may provide favorable conditions for agriculture and forest, and improve their potential production. 相似文献